Thermal insulation



Patented Ma 21, 1935 THERMAL INSULATION Martin C, Hnggett, Chicago, Ill., assignor, by

mesne assignments, to Research Inc., a corporation of Illinois No Drawing. Application September 30; 1933,

Serial No. 691,696

2 Claims. (c1. 154-44) This invention relates to thermal insulation.

It is an object of this invention to provide an improved thermal insulation which is relatively simple and inexpensive in construction and emcient in use. t

Thermal insulation in the form of metal foil carried by a frame, and thermal-insulating sheets having a metallic heat-reflective surface or coatingare well known in the prior art as represented by the following patents: U. S. Patents Nos. 1,757,479, 1,890,418, 10,375, 289,505, 294,780, 1,306,- 281, 1,383,680, 1,445,070, 1,757,479, 1,667,691; British Patents 266,177 (1927); 310,572 (1929); 317,- 678 (1929) and German Patent No. 529,867 (1931). These patents pretty well represent the prior art in thermal insulation and they show the development of thermal insulation including the use of thermal insulating sheets having a metallic coating thereon and functioning as the active, heat-reflective constituent thereof. There are, however, serious objections to, 'anddifliculties experienced in the use of, thermal insulation in the ,form of metal foil as well as in form of sheets having a metallic coating or'heat-reflective surface. Among these objectionable features are: The usual vform of metal used for thermal insulation and coatings therefor is either a' metal foil car available for use it is necessary to install them in rigid frames with the foil or coated sheet stretched and securely fastened in .the frames. This construction is-very impractical in building construction which requires a flexible, tough material which can be subjected, without damage, to rough handling, creasing, and abrasion.

Another objection to the prior art metal foils ormetaliized heat insulation sheets is that their metallic content upon exposure tov acids, alkalis, and atmospheric conditions corrodes, tarnishes, and deteriorates generally, and thereby loses much of its heat-reflective power and emciency. This is true whether the metallic insulation sheet be in the form of a'metal foil or in the form of a foilcovered vegetable or cellulose base sheet or a base sheet havinga metallic powder spread thereover.

Objects of this invention, therefore, are: to provide a thermal insulating sheet which in use overcomes the aforementioned and other difliculties experienced in the use of the prior heat insulators; to provide a thermal insulation sheet having a highly polished, silver-colored non-metallic coating or heat-reflective surface; and to provide a thermal insulation sheet that is relatively inexpensive to manufacture, which is flexible and tough, which can be subjected to rough handling and abrasion without damage; which is unaffected by weather conditions and the presence of acids and alkalis; which can be creased and folded 5 without breaking or cracking its reflective surface; which is waterproof and moisture proof; and which is generally emcient as a. heat insulator in all of the uses to which it may be put.

The aforementioned objects may be accomplished and the hereinbefore referred to and pres ent non-metallic heat insulation sheet produced in many different ways and by using many different formulas, or constituents, some of which will be indicated hereinafter. However, a typical example of a satisfactory formula and method for making a typical specimen of the new thermal insulation sheet is as follows:

Formula and Example 1 (Agzs), 40 per cent casein, and 10 per cent wax, I may be applied to a suitable vegetable base sheet which may be, for example, a sulphite or craft paper or the like. This composition may be applied to the base sheet in any suitable manner as by hand, by means of an automatic brush, known as a brush-coater; or by the rolls of a coating machine; or the adhesive 'cuein may be spread over the base sheet and the silver sulphide spread thereover as a dry powder as by dusting, sifting, or spraying. The base sheet-thus coated may then be placed in a friction calender having its rolls heatedto approximately from 300 to 400 F. and pressure then applied. This treatment changesv the coating from either .a cubic black or dark gray color to a highly polished bright silver 40 color and produces a thermal insulating sheet having a bright, highly polished surface that is highly reflective to heat and which sheet has the other desirable qualities hereinbefore mentioned,

being tough, flexible, moisture proof, and weatherground wood; a combination of craft paper, sul- .phite paper, ground wood, and waste mixed pa-' pers; or any combination of the above; or any fibrous material including silks, cottons, rayons, woolens, linens, or wood; or metal, glass or other surface.

As examples of other heat-reflective pigments or active constituents that may be used' in the finely divided state in place of silver sulphide in the manufacture of the aforementioned coating and heat-insulating sheet described in Example No. 1, as well as in the other coating compositions to be described hereinafter, are the following: litharge, aluminum oxide, stephanite, (a silverantimony. sulphide, Ag2SbS),' Dyrargyrite (AgSbS); horn silver (silver chloride, AgCl), infusorial or diatomaceous earth, augite, a volcanic mineral of a black or greenish color, diallage, a mineral allied to augite having a brown. ray, or green color, laminated in structure, and having a metallic lustre when broken across; alunite, a boric sulphate of potassium and aluminum, or any other heat-reflective substance which is nonmetallic and which can be finely divided and highly polished to give a silver sheen.

As examples of vehicles or carriers in which the silver sulphide in the above example, or any of the other heat-reflective constituents or pigments herein indicated may be used are: beeswax,

- paraflin wax, petroleum tailings, china wax, or

any other wax whether it be soluble or insoluble in water, acid-resisting casein, or any casein in combination with formaldehyde; nitrocellulose; cellulose acetate; any phenol resin in combination with any asphalt derivative; any coal tar derivative; linseed oil or combinations thereof; starches; or any other vehicle that will act as an adhesive or binder and which will at the same time carry the aforementioned pigments or active .heatreflective constituents of the new heat-reflective coating composition and heat-insulating sheet.

The heat reflective coating formula recited in Example 1, above, may be replaced by any of the following formulas, all proportions indicated being by weight unless otherwise specified:

Formula 2.-20 percent silver sulphide,finely divided; percent casein in combination with formaldehyde; and from 5 per cent to 10 per cent of a suitable wax, which may be any of those hereinbefore mentioned;

Formula 3.-8 oz. of 60 second cotton; one quart of ethyl acetate;vone quart of toluol; gal. of benzol or benzine mixed with castor oil, tricresyl phosphate and butyl acetate;- and 2 lbs. of finely divided silver sulphide or any of the other heatreflective constituents or pigments herein indi-.

cated; v

Formula 4.1 lb. of cumar; '10 per cent of soy bean oil; 20 per cent of naphtha; and 2-lbs. of finely divided silver sulphide orother pigment hereinbefore named; v

Formula 5.--3 lbs. of feculose casafin 9 parts of water one part of inverted sugar: and 2 lbs. of finely divided silver sulphide, or other heatreflective pigment herein named;

Formula 6.l gal. of China-wood oil; $5 lb. of

litharge; 2 lbs. ofresin; and 1 gal. of boiled linseed oil'. This mixture is cooked to about 475 F. and the temperature allowed to drop to about 350F. A suitable quantity of naphtha is then added to the mixture; and finally to that mixture is added 1% m2 lbs. of finely divided silver sulphide or any of theother non-metallic or mineral heat-reflective pigments hereinbefore named.

Among the products that may be produced employing the thermal insulation sheet made as hereinbefore taught are the following:

-Product A.This product is a heat insulation fabric particularly designed for use in building construction and may be made by applying any one of the aforementioned coating compositions to one side or surface of a sheet of sulphite paper. Two sheets of thiss'ulphite paper thus coated are put through a duplexing machine with their uncoated surfaces back to back, and asphalt or other adhesive is applied to the untreated surfaces of the coated sulphite sheets; while simultaneously therewith a reenforcing' fabric or web of jute, flax, cotton, or metal is introduced between the sheets and thoroughly covered with asphaltum or other adhesive; and finally the two sheets having the reenforcing web therebetween are united by passing them between two rolls while applying sufficient pressure to form all of these materials into a single, homogeneous heat insulation sheet having highly effective heatrefiecting non-metallic coatings or surfaces on both sides thereof. d Product B.This product is a heat insulation board particularly designed for use in building construction, and may be produced by coating one surface of a four or five. ply pulpboard with any one of the above-named formulas. The process of manufacture is as follows: A heat-reflective surface coating is applied to chipboard, as above described, and this layer of chipboard, thuscoated, is then combined with three or four layers of the same material in the usual manner of combining or uniting pulp board, or so-called wall-boards, thereby leaving one heat-reflective surface exposed.

Product C'.-This product is an industrial insulation sheet particularly designed for use in the refrigeration industry and may be made by apply g any one of the heat-reflective coating compositions above enumerated, and in the manner described, to one side of a suitable craft paper, which may be paper of from 30 to 100 lbs. weight, approximately.

The aforementioned products and uses illustrate the wide application and the variety of uses to which the new heat-insulating sheet may be put but they are illustrative rather than limitative since the present heat-insulating sheet may also be used in many other ways and places, and among which are:

In the automobile industry, for use .in automobilertops and in the refrigeration industry where tests of its use show considerable reductions in ice and electricity consumption when using this product; and as a heat-reflective surface behind or in back of radiators; while any one of the aforementioned coating compositions itself may be applied to sheet metal in the manufacture of radiator cabinets. When so used the coating composition adds greatly to the eillciency of the radiator cabinet. These products may also be used for porch screens, Billll'OOlll screens,

dow screens, arranged behind plate glass to event frost accumulation; as window shades to reilect the sun's heat and to prevent it from entering a room or building; and in other ways.

kperimental data in the applicant's possession. and made upon test samples of certain 01' the products hereinbetore named, show that these products are emcient heat insulators; that their heat conductivity is less than, and consequently their heat insulating emciency greater than, the usual vegetable board or sheet insulators, and metallic foil or metal-coated insulators now in use.

By way of recapitulation .it may, therefore, be said that the present invention contemplates essentially a heat-insulating and reflective sheet consisting oi! a base having a highly polished, heat-reflective coating spread thereover and the heat-reflective coating consisting, essentially oi. an adhesive vehicle or carrier having incorporated therein a finely divided, non-metallic substance which is capable of being highly polished to provide a bright, silver-colored heat-reflective surface.

By the term non-metallic" as used hereinhefore, and as used hereinafter in the claims. is

meant any-substance other thanametal, that is, other than a simple elementary metal such, for example, as aluminum ioilor powder, but including mineral, -as well as non-mineral substances and vegetable and mineral substances, which are capable of being finely divided and spread upon and adheredtoabase orbase sheetyand which can be highly polished to provide a bright, silvercolored heat-reflective surface.

Having thus'described my invention what I claim as new and desire to protect by letters Patent is;

.1. A thermal insulation unit consisting of a base sheet having thereon a highly polished heatreflective non-metallic mineral film; said him having a heat-reflective power approximating that of polished silver.

2. A thermal insulation unit including a base sheet having thereon a highly polished heat-reflective non-metallic mineral mm; said illm having a heat-reflective power approximating that of a metal MARTIN C. HUGGI'l'l.

relatively eillcient heat-reflective polished 

